An imaging apparatus capable of capturing still images and moving images has been widely known in the past (see, for example, Patent Document 1 below).
In an imaging apparatus described in Patent Document 1, analog image data acquired in an imaging device is output to an analog signal processing unit. The analog image data, which has been output to the analog signal processing unit, is subjected to analog signal processing (amplification and the like) and then output to an A/D (analog-digital) conversion unit to be converted into digital image data. The digital image data is output to a digital signal processing unit and subjected to noise removal processing, white balance processing, color correction processing, edge enhancement processing, gamma correction processing, and the like in the digital signal processing unit. The digital image data, which has been subjected to those processing, is then output from the digital signal processing unit, and the image data is displayed on a liquid crystal panel and also stored in a recording device.
In order that the image data, which has been output from the imaging device, is output from the digital signal processing unit as image data of an appropriate exposure amount, a method of adjusting an exposure amount within the digital signal processing unit may be used. However, at the time of A/D conversion by the A/D conversion unit, image data of extreme brightness may impair part of gradation thereof at the time of A/D conversion. For that reason, there is a problem that the part impaired at the time of A/D conversion cannot be restored in the digital signal processing unit.
So, in general, a method of adjusting an electronic shutter (adjusting an exposure time in the imaging device), a method of adjusting an aperture of a diaphragm, and the like are used.
Patent Document 1: Japanese Patent Application Laid-open No. 2012-104994 (see paragraphs [0038] and [0055] and FIG. 3)